Hello!
I found the EPartService which allows me to listen to the parts,
when they are activated, deactivated, shown, hidden.

Is it possible to know when a part is closed?
Or what would be the right way to clean up the resources?

And again: I need to listen for the Part cycle from "outside"
(I will do something with a Shell, when the part is shown)
Further I wouldn't like to add a special @OnDestroy annotated method to the part, since my methods would only work with that parts, which would contain this method.